Treatment of Skeletal Open Bite With Open Bite Activator and Skeletal Anchorage-Supported Vertical Elastics (SOBT)

Ankara University

Status: Completed

Conditions: Long Face Syndrome; Vertical Maxillary Excess; Skeletal Open Bite; Hyperdivergent Growth Pattern

Treatments: Device: Open Bite Activator with Skeletal Anchorage-Supported Vertical Elastics

Study type: Interventional

Funder types: Other

Identifiers

NCT06936371

AUFDT-ORT-2021-22

36290600/22

Details and patient eligibility

About

This study evaluated a new treatment approach for skeletal open bite in growing individuals using an open bite activator combined with anterior skeletal anchorage-supported vertical elastics. An open bite is a condition where the front teeth don't touch when the back teeth are closed together, creating a gap. Traditional treatments often use extraoral appliances (devices worn outside the mouth), which can be uncomfortable and aesthetically unappealing, leading to poor patient compliance.

We included 24 growing patients (14 females, 10 males) aged 12-14 years with skeletal open bite. All participants received an open bite activator (a removable functional appliance) and mini-screws placed between the upper and lower lateral and canine teeth. Vertical elastics were connected between these mini-screws, applying 150g of force for 20-22 hours daily over 12 months.

Lateral cephalometric radiographs (specialized X-rays) were taken before treatment and after 12 months to evaluate changes in facial bone structure and tooth positions. Our results showed successful correction of open bite with an average increase in overbite of 3.35mm. We observed favorable skeletal changes including clockwise rotation of the maxilla (upper jaw), counterclockwise rotation of the mandible (lower jaw), and decreased vertical facial dimensions.

This treatment approach offers a viable alternative to conventional methods that rely on extraoral appliances, potentially improving patient comfort and compliance. The protocol successfully addresses both skeletal and dental components of open bite malocclusion in growing patients.

Full description

Detailed Description This prospective interventional study aimed to develop and evaluate a novel treatment protocol for skeletal open bite that eliminates the need for extraoral appliances while achieving comparable therapeutic outcomes. Skeletal open bite represents a challenging orthodontic condition characterized by increased vertical facial dimensions, divergent skeletal planes, and negative overbite.

Our treatment protocol combined two therapeutic approaches: (1) a modified open bite activator constructed with 3-4mm addition to the freeway space and relief in the anterior region, and (2) skeletal anchorage using mini-screws placed in the anterior region between lateral and canine teeth in both arches, connected by vertical intermaxillary elastics.

The open bite activator component functioned through multiple mechanisms: acting as a posterior bite block to inhibit posterior dentoalveolar eruption, serving as a tongue barrier to prevent tongue thrust between anterior teeth, and directing masticatory forces to the posterior segments. The anterior relief in the appliance allowed for uninhibited eruption of incisors. The vertical elastics between mini-screws provided controlled force (150g) to facilitate favorable rotational movements of the maxilla and mandible.

Cephalometric analyses included comprehensive skeletal angular measurements (SNA, SNB, ANB, Y Axis, SN/PP, GoGn/SN, PP/MP, gonial angle), skeletal linear measurements (N-Me, ANS-Me, Co-Go, S-Go), skeletal proportional measurements (Jarabak ratio), dentoalveolar angular measurements (U1-PP, interincisal angle, IMPA), and dentoalveolar linear measurements (overjet, overbite, U1-PP, U6-PP, L1-MP, L6-MP).

This treatment protocol demonstrates the potential to achieve effects similar to traditional approaches using posterior high-pull headgear and vertical chin cup, without compromising treatment outcomes. The significance of this approach lies in its ability to address a primary challenge in orthodontic treatment of growing patients with skeletal open bite: patient compliance and comfort, which often determines treatment success.

Enrollment: 24 patients

Sex: All

Ages: 12 to 14 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Growing individuals aged 12-14 years
• Diagnosis of skeletal open bite with GoGn/SN angle ≥36°
• Dentally reduced or negative overbite
• Ongoing growth and development (confirmed with hand-wrist radiographs)
• Good oral hygiene
• No prior orthodontic treatment or orthognathic surgery
• No systemic disease or craniofacial deformity
• Informed consent obtained from participant and parent/guardian

Exclusion criteria

• Presence of any craniofacial anomaly or systemic condition affecting craniofacial growth
• History of prior orthodontic treatment or jaw surgery
• Poor oral hygiene
• Non-compliance with appliance wear protocol
• Outside the age range of 12-14 years

Trial design

Primary purpose: Treatment

Allocation: N/A

Interventional model: Single Group Assignment

Masking: None (Open label)

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24 participants in 1 patient group

Functional Appliance and Skeletal Anchorage Group

Experimental group

Description:

This arm includes growing individuals with skeletal open bite treated using a combination of an open bite activator (functional appliance) and vertical intermaxillary elastics supported by anterior skeletal anchorage (mini-screws placed between lateral and canine teeth in both jaws). The appliance was worn full-time for 12 months. Cephalometric changes were evaluated before and after treatment to assess skeletal and dentoalveolar effects without the use of extraoral appliances.

Treatment:

Device: Open Bite Activator with Skeletal Anchorage-Supported Vertical Elastics